1. Field of the Invention
The present invention relates generally to infrared tracking systems, and more particularly, to input devices and methods for user interaction with a computer system utilizing an infrared tracking system.
2. Description of the Related Art
Conventional video-based tracking systems have been employed in Virtual Reality (VR) and Augmented Reality (AR) systems to track locations of real-world objects and to estimate the pose, i.e. the position and orientation, of a user of the aforementioned systems. Recent advances in both hardware and software have made it possible to build infrared tracker systems that can run on regular computers with off-the-shelf cameras and low-end video capture boards. An infrared video-based tracker consists of a camera with an infrared-filter lens, a capture board, a set of light-emitting diodes (LEDs) that radiate light in the infrared band, and a set of retroreflective patches or markers. The video obtained from the camera through the capture board is processed on a processor to identify the images of the retroreflective patches within. Because of the filtering of the camera, the only visible segments of the video will be the ones corresponding to the retroreflective markers in the scene. This makes the identification process quite fast yet requires low processing power. In fact, the infrared video-based tracker can easily operate at full frame rates (30 frames per second) without overloading the system processors.
Furthermore, the infrared video-based tracker can also be realized by using a chip on board the camera. Since the identification process is quite simple, it is possible to put the identification algorithm on a small chip that can be placed on the camera itself. This will reduce the processing requirement to zero on the main system processor.
Similar technological advances in wearable computers equipped with wearable displays, such as head-mounted displays (HMDs), necessitated new means of input and interaction with these wearable computers. The conventional means of input and interaction with these new types of computers, such as a mouse and keyboard, are not adequate and have proved to be very cumbersome. More elaborate methods of interaction, such as speech driven ones, have not come to a mature state yet. They are either too hard to integrate due to their inherent difficulties, such as “training” the speech driven system, or require quite a bit of processing power overloading the processor on these wearable computers which tend to be less powerful compared to conventional ones.